这是一篇外国人写的关于最优化方法中共轭梯度法的通俗易懂的介绍，文中用了大量的图形来解释相关概念和公式的几何意义。不过，需要一定的英语阅读能力。-This is a user-friendly introduction to a foreigner on the optimal method of conjugated gradient method, the paper uses a large number of graphics to explain the geometric meaning of the concepts and formulas. However, some English reading ability.